All right now everyone, think hard:HOW did you learn these theories? Seriously, who told you? A very good windsurfer, perhaps a pro? A shop owner? A fin maker? That guy who dulls his fins to protect his feet from cuts? The guy who cuts out his own freestyle fins, who rarely sails over 15 mph?

Sorry to get so snarky, but the endless unsubstatiated claims on this forum get to me after a while. I don't claim to be the all-knowing guru of all things windsurfer, that's ISOBARS, but I've done a lot of personal testing and experimenting over the last 23 years of sailing, and I know what actually works and what is basically wives' tales.

However, since I'm NOT infallible, I sat down with someone who could give me some serious scientific input on this subject, Dr Clint Harper. I have the good fortune to work at Moorpark College here in SoCal, where Dr. Harper is the chair of the Physics dept., and a sailboat owner (that's his latest boat in the picture).

I sat down with Dr. Harper today, and discussed the various aspects of this discussion. The short version is: Sand your hull if you want to, keep your fins smooth. Some of the stuff in this thread is accurate, but mostly it's just stuff somebody heard from someone they consider believable. I sometimes do that, but this is one subject I'm very mental about, as I sail mostly slalom, and love to speed sail (went 40 mph. a couple times). Sanding your hull is scientifically proven to work at sailboat speeds, but my feeling is how much will you gain, 1/2 mph? I'm not on the World Cup tour, so would rather have the extra epoxy on there.

Sanding your fin could cause the laminar flow to detach, which leads to spinout.

If you wish to dispute my assertions, please refer to the photograph, and make sure your source of infomation has a PhD (or better) in physics, and owns their own sailboat.

Most dolphins are faster than the average shark. However some sharks are much faster. The blue shark is a very fast shark with speed bursts recorded over 40 mph. And the fastest shark the short finned mako shark is the fastest, with speeds spurting over 60 mph.

more than 1 answer :

While some sources claim that both dolphins and sharks can swim at speeds of over 60 mph, these reports are few and far between. Most experts agree that the top speed of some shark species is about 30mph, while dolphins most dolphins can only get up to 20mph.

as seen ::

No scientific research actually shows that dolphins are faster then sharks for one reason. They can swim about 24 miles an hour next to a boat for ten to thirty minutes which a shark could only swim for a short amount of time to catch it's food. It's like a speed boost. So dolphins are faster then sharks!_________________K4 fins
4Boards....May the fours be with you

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